Button for electrical switch or the like

ABSTRACT

For use with an electrical switch having a manually movable actuating blade, a button comprising a solid metal block having a slot in one end for receiving the blade, and cylindrical nylon insert members press-fitted into recesses formed in the block along the sides of the slot for engagement with the side edges of the blade, the insert members being compressed by the blade so as to hold the button securely on the blade.

United States Patent 191 [111 3,809,841 Rico [451 May 7, 1974 [54] BUTTON FOR ELECTRICAL SWITCH OR 2,706,774 4/1955 Bowman 200/172 R X THE E 2,221,558 11/1940 Rubinstein 200/172 R 2,151,626 3/1939 Travers 200/172 R X Inventor: Luis Edgar Rico, 98-17 Horace 2,069,427 2/1937 sum zoo/172 R x Harding Exwy., Rego Park, NY. 11363 Primary Examiner-Robert K. Schaefer 22 Filed; June 27 1973 Assistant Examiner-William J Smith' Attorney, Agent, or FirmCooper, Dunham, Clark, [21] Appl. No.: 374,258 G iffi & Moran g [52] U.S. Cl. .(film/329,4&733146536? 57 ABSTRACT [51] Int. Cl. I:l01h 3/12 For use with an electrical switch having a manually [58] Field of Search..... ZOO/172R, 159 R, 403/354,

403 movable actuating blade, a button comprising a solid metal block having a slot in one end for receiving the blade, and cylindrical nylon insert members press- [56] References cued fitted into recesses formed in the block along the sides UNITED STATES NT of the slot for engagement with the side edges of the 3,627,363- 12/1971 Van Buren"; 403/365 blade, the insert members being compressed by the 3,601,431 3/1971 Henley 403/372 X blade so as to hold the button securely .on the blade. 2,937,042 5/1960 Wilder 403/354 2,917,349 12/1959 6 Claims, 8 Drawing Figures Saylor et a1 403/365 X BUTTON FOR ELECTRICAL SWITCH OR THE LIKE BACKGROUND OF THE INVENTION This invention relates to handles or buttons for electrical switches and the like. Specifically, it relates to switch buttons of the press-on type.

Many electrical switches include a manually movable actuating member, typically in the form of a freeended, axially rectilinear blade having two or more lateral flanges with parallel side edges, over which a button is fitted to facilitate manual operation of the member as well as to provide an attractive or decorative appearance. For example, in a pushbutton switch, the actuating member is a reciprocable blade projecting from the body of the switch; a button is fitted over the free end of the blade to be engaged and pushed by a finger of a human operator.

One type of button structure widely used with electrical switches is a so-called press-on button, i.e. a button (having an appropriately shaped slot or recess which is simply pressed or pushed over the free end of a switch blade in a direction parallel to the blade axis. An advantage of this type of button is that it may be easily and rapidly installed, without use of tools, after the switch is mounted within a housing structure; commonly, the switch blade is arranged to project through a relatively small opening in a housing, and in such case, it is not practicable to fixedly secure a button to the blade prior to mounting of the switch.

Desirably, a press-on button should be structurally simple, and capable of being removed and remounted e.g. incident to repair or other disassembly of the apparatus in which the switch is incorporated; yet it should also be firmly secured to the blade so that it will not become accidentally detached from the blade during use. l-leretofore, it has been difficult to achieve ensured adequately secure engagement between press-on buttons and switch blades without sacrifice of structural simplicity, ease of installation, and/or removability of the button.

SUMMARY OF THE INVENTION An object of the present invention is to provide a new and improved press-on button which is simple and durable in structure, readily installed, easily removed and remounted, and which affords enhanced security of engagement with a switch blade when mounted thereon.

To this and other ends, the invention broadly contemplates the provision of button structure comprising a solid metal body having an axially rectilinear slot formed in one end for receiving a free end of a switch blade with a clearance fit when, the button body is pressed or pushed in an axial direction over the blade free end, each side of the slot being enlarged to form a recess axially parallel to the slot; and a plurality of resiliently compressible insert members respectively press-fitted into these recesses for lateral engagement with the parallel side edges of the blade when the blade is received within the slot. The disposition of the recesses is such that the blade edges laterally compress the insert members, and in consequence the insert members exert opposing forces on the blade, in directions perpendicular to the direction of axial movement of the blade into and out of the slot; these forces effectively clamp the blade within the slot, thereby securely holding the button on the blade.

The aforementioned recesses, and also the insert members (which are preferably fabricated of nylon) may be of cylindrical configuration. As a specific feature of the invention, the recesses extend into the metal body to a depth greater than that of the slot, so that the inner extremities of these recesses constitute fully laterally enclosed sockets for receiving and securely holding the bases of the insert members. The recesses and the slot open outwardly through a common end face of the metal body, through which the insert members are introduced' to the recesses in an axial direction. The metal body is sufficiently thick, on each side of the slot, as to be essentially rigid.

In a broad sense, the button structure of the invention may be adapted for use with a switch blade having two, three or more radial flanges, the slotbeing shaped to conform to the cross-sectional configuration of the blade and having an insert-member-holding recess disposed for register with the lateral edge of each flange of the blade. The forces exerted by the insert members on the flange edges are directed radially inwardly, i.e. toward the axis of the blade. Again stated broadly, a button embodying features of the invention may be adapted for use with a switch blade of reciprocating (push-button), rotary or other type. It will be understood that the term switch blade as herein used refers to a free-ended projecting member which is manually movable to actuate an electrical switch.

The invention in one specific embodiment, adapted for use with a flat reciprocating switch blade having opposed parallel side edges (wherein the opposite side edge portions of the blade are herein considered as constituting a pair of opposed radial flanges integral with the blade, which may be a unitary flat metal member), comprises a rectangular solid metal body having a blade-receiving slot in one end with axially parallel cylindrical recesses formed along opposite sides of the slot, and a pair of cylindrical nylon insert members press-fitted therein. The slot may also include an enlarged central bore portion for accommodating the end of a helical return spring incorporated in the switch blade structure. The nylon insert members, when compressed radially by the opposite side edges of the blade within the slot, exert opposed forces on the blade, securely clamping the blade between them.

Further features and advantages of the invention will be apparent from the detailed description hereinbelow set forth, together with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of a button structure embodying the present invention in a particular form, as mounted on a switch of the push-button type;

FIG. 2 is an enlarged plan view, partly in section, of the button and switch of FIG. 1;

FIG. 3 is an enlarged perspective view of the button of FIG. 1;

FIG. 4 is a sectional view taken along the line 4-4 of FIG. 2;

FIG. 5 is a sectional view taken along the line 5-5 of FIG. 2;

FIG. 6 is a sectional view taken along the line 6-6 of FIG. 2; and

FIGS. 7A and 7B are enlarged fragmentary sectional views similar to FIG. 6 respectively illustrating the cross-sectional shape of one of the insert members of the FIG. 1 button structure when the blade of a switch is present in and absent from the slot of the button.

DETAILED DESCRIPTION For purposes'of specific illustration, the present invention will be described as embodied in a button structure adapted for use with a push-button electrical switch of the type shown at in FIGS. 1 and 2. This switch, which may be generally conventional in character, includes operative mechanism (not shown) for making and breaking an electrical circuit, enclosed within a housing structure 11. An axially reciprocable actuating blade 12, having a free end 14, projects through an opening in a side wall of the housing 11 and is connected to the aforementioned operative mechanism in such manner that reciprocating movement of the member 12 causes an electrical circuit to be opened or closed.

The blade 12 as shown is a flat metal member having opposed parallel side edges 15 and 16. The side portions 17 and 18 of the blade may be considered as constituting opposedcoplanar radial flanges, i.e. flanges extending laterally of the blade in opposite directions from the rectilinear axis thereof. A central opening 19 is formed in the blade to accommodate a helical spring 20 disposed in coaxial relation to the blade; this spring, under compression between the blade and fixed structure, urges the blade in an axial direction away from the housing 11. The structure and operation of a pushbutton electrical switch blade of the described type are well known in the art and accordingly need not be described in further detail.

As adapted for use with the aforementioned blade 12, the button structure of the invention in its illustrated embodiment comprises a rectangular solid metal body 25, e.g. fabricated of aluminum, having in one end portion 26 a slot 28 (FIG. 3) for receiving the free end portion 14 of the blade 12. Slot 28 longitudinally bisects the end face of the body at 26 and extends therefrom into the'body, e.g. for a distance equal to about one-third the length of the body, intermediate and parallel to the opposite major surfaces 29 and 30 of the body. Conveniently the slot 28 may be formed by making a saw cut through the end portion 26 of the body, so that the slot opens through the end face of the body and extends from side to side thereof, opening also through adjacent portions of the side surfaces 31 and 32 of the body. The dimension of the body 25 between sides 31 and 32 is substantially greater than the width of the switch blade 12; hence the corresponding dimension, or width, of the slot 28 thus formed is similarly greater than the width of blade 12. It will be understood that the openings of the slot through the sides of the body 25 occur incident to formation of the slot by a saw cut, and that the slot may alternatively be formed in other ways wherein no openings are made in the sides of the body.

The transverse dimension of the slot 28, i.e. in a direction perpendicular to surfaces 29 and 30, is at least slightly greater than the thickness of blade 12 to provide a clearance fit between the blade and the slot walls I when the blade is inserted in the slot. At the central portion of its opening through the end face of the body at 26, the slot 28 may be enlarged by a bore 34 to accommodate the end of spring 20 engaging blade 12, as best seen in FIG. 4. The axis of this bore may be coinci- '4 dent with the longitudinal axis of the body 25, which is also the axis of symmetry of slot 28 to which reference will hereinafter be made as the slot axis.

At each side of the body 25, but inwardly of the side surfaces thereof, the slot 28 is enlarged to form a pair of cylindrical recesses 36 and 38 which open through the end face of the body at 26 and extend therefrom into the body in axially parallel relation to each other and to the slot. These recesses, which have equal diameters greater than the aforementioned transverse dimension of the slot 28, are spaced apart by a distance slightly less than the width of the blade 12. As shown in FIGS. 2 and 3, the two recesses 36 and 38 extend into the body to a depth somewhat greater thanthe depth of slot 28 so that the inner extremities of the recesses constitute fully laterally enclosed sockets.

A pair of resiliently compressible cylindrical insert members 40 and 42 are respectively press-fitted into the recesses 36 and 38, being introduced through the end face of the body at 26. These insert members in unstressed condition have a diameter slightly greater than the diameter of the recesses 36 and 38 so that they fit snugly within the recesses and are of such length that they seat in the aforementioned sockets at the inner ends of the recesses while their outer ends are substantially flush with the end face of the body at 26. When the insert members are received within the recesses 36 and 38, longitudinal surface portions of the insert members face each other across the slot 28 and effectively constitute side walls of the slot, being spaced apart by a distance slightly less than the width of the blade 12.

The described insert members 40 and 42 may be fabricated of a suitably durable, wear-resistant plastic material somewhat more readily compressible than the metal of the body 25, yet nevertheless relatively resistant to compression. One especially suitable and presently preferred material for these insert members is nylon; i.e. in the illustrated embodiment, members 40 and 42 are short solid nylon rods.

The use of the described button structure may now be readily explained. Body 25 is held e.g. manually with the end portion 26 facing blade 12 of the switch 10, and the blade is then inserted in the slot 28 between the insert members 40 and 42 by manually pressing the button onto the blade as far as it will go in a direction parallel to the axis of the blade, i.e. until the free end 14 of the blade seats against the inner extremity of slot 28.

Since the distance between the facing surface portions of insert members 40 and 42 within the slot is slightly less than the width of the blade 12, the side edges 15 and 16 of the blade respectively press against and compress the insert members 40 and 42 as the blade is inserted in the slot. This compression is illus- When thus compressed, the insert members 40 and 42 (being substantially resistant to compression) respectively exert opposed forces on the blade 12, these forces being directed laterally of the blade, i.e. toward the axis thereof from opposite directions perpendicular In this way, secure attachment of the button body 25 to the blade 12 is achieved without use of tools or auxiliary fastening means such as set screws. It is found that the clamping action resulting from the compression of the insert members 40 and 42 is fully effective to prevent accidental dislodgement of the button from the blade, although the button may be removed from the blade if desired by exerting a strong pulling force on the button in an axial direction away from the blade. Ordinary pulling forces such as may be exerted on the button to displace the button outwardly relative to the switch, i.e. incident to use of the switch, do not dislodge the blade.

The insert members 40 and 42 are securely held in the socketed recesses 36 and 38 even when the button is pulled off the blade. It may be explained that the rigid metal body 25 is of sufficient thickness, on each side of the recesses 36 and 38, to be essentially free from deformation incident to insertion and removal of the blade. This rigidity of the metal body cooperates with the insert members in maintaining strong and secure attachment of the button to the blade.

In a specific example of construction of the described embodiment of the invention, with a metal body having a thickness of 0.375 inch (between surfaces 29 and 30) and a width ofO.680 inch (between surfaces 31 and 32) and a slot having a transverse dimension of 0.043 inch and a depth of 0.312 inch, recesses 36 and 38 (0.375 inch deep and spaced apart 0.560 inch on centers) have a diameter of 0.093 inch; thus the thickness of the aluminum body, on each side of each recess (i.e. between the recess and the adjacent surface 29 or 30) is about 0.141 inch, i.e. substantially greater than the recess diameter. In this example, each of the nylon inserts 40 and 42 is compressed 0.008 inch by insertion of the switch blade within the slot. This extent of compression is found to afford highly secure attachment of the button to the blade.

It is to be understood that the invention is not limited to the features and embodiments hereinabove specifically set forth but may be carried out in other ways without departure from its spirit.

I claim:

1. For use with a switch including a manually movable actuating blade having an axially rectilinear free end portion and at least two lateral flanges with side edges parallel to the axis of the free end portion, button structure comprising a. a rigid solid body having a slot formed in one end thereof for receiving the free end of the blade with clearance, said slot having sides corresponding in number and disposition to the sides edges of the flanges of the blade, each of said slot sides being enlarged to form a recess axially parallel to the slot and opening through said one end of said body; and

b. a plurality of resiliently compressible insert members respectively press-fitted into said recesses for lateral engagement with the side edges of the blade when the blade is received within the slot;

c. said insert members being disposed for lateral compression by the blade edges in such respective directions that the insert members exert opposing forces on the blade directed toward and perpendicular to the blade axis for clamping the blade within the slot.

2. Structure as defined in claim 1 wherein said recesses and said insert members are substantiallycylindrica].

3. Structure as defined in claim 2 wherein said recesses extend into said body to a depth greater than the depth of said slot such that the inner ends of the recesses are fully laterally enclosed sockets for receiving the inner ends of said insert members.

4. Structure as defined in claim 1 wherein said insert members are fabricated of nylon.

5. For use with an electrical switch including a blade having an axially rectilinear free end with opposed parallel side edges, button structure comprising a. a solid metal body having an end face and a slot opening through said end face and extending into said body for receiving the blade with clearance, opposite sides of the slot being enlarged to form cylindrical recesses axially parallel to the slot; and

b. a pair of cylindrical nylon insert members respectively press fitted into said recesses for lateral engagement with the opposite side edges of the blade when the blade is received within the slot;

0. said insert members being disposed for lateral compression by the blade in opposite directions such that the insert members exert opposing forces on the blade directed toward and perpendicular to the axis of the blade for clamping the blade within the slot.

6. Structure as defined in claim 5 wherein said body has a thickness, on each side of each of said recesses,

greater than the diameter of the recess.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 3 309.8 41 I Dated f May 7 19714 lnventor(s) Luis Edgar Rico It is certified that error appears in the aboveidentified patent and that said Letters Patent are hereby corrected as shown below:

Cover Sheet; Column 1, lineB, change "i761" to after line 5 insert the following [3 3] Assignee: The Sequerra 00., Ina,

Woodside NewjYork Signed amt? sealed this .19th day of Novez'siber 197 (SEAL) Attest:

McCOY Ms GIBSON JR. C. MARSHALL DANN Atteeting Officer Commissioner of Patents FORM PO-1050 (10-69) U COM Dc I S M- 6376P69 UIS. GOVERNMENTPRINTING OFFICE: '969 365"33-$ 

1. For use with a switch including a manually movable actuating blade having an axially rectilinear free end portion and at least two lateral flanges with side edges parallel to the axis of the free end portion, button structure comprising a. a rigid solid body having a slot formed in one end thereof for receiving the free end of the blade with clearance, said slot having sides corresponding in number and disposition to the sides edges of the flanges of the blade, each of said slot sides being enlarged to form a recess axially parallel to the slot and opening through said one end of said body; and b. a plurality of resiliently compressible insert members respectively press-fitted into said recesses for lateral engagement with the side edges of the blade when the blade is received within the slot; c. said insert members being disposed for lateral compression by the blade edges in such respective directions that the insert members exert opposing forces on the blade directed toward and perpendicular to the blade axis for clamping the blade within the slot.
 2. Structure as defined in claim 1 wherein said recesses and said insert members are substantially cylindrical.
 3. Structure as defined in claim 2 wherein said recesses extend into said body to a depth greater than the depth of said slot such that the inner ends of the recesses are fully laterally enclosed sockets for receiving the inner ends of said insert members.
 4. Structure as defined in claim 1 wherein said insert members are fabricated of nylon.
 5. For use with an electrical switch including a blade having an axially rectilinear free end with opposed parallel side edges, button structure comprising a. a solid metal body having an end face and a slot opening through said end face and extending into said body for receiving the blade with clearance, opposite sides of the slot being enlarged to form cylindrical recesses axially parallel to the slot; and b. a pair of cylindrical nylon insert members respectively press fitted into said recesses for lateral engagement with the opposite side edges of the blade when the blade is received within the slot; c. said insert members being disposed for lateral compression by the blade in opposite directions such that the insert members exert opposing forces on the blade directed toward and perpendicular to the axis of the blade for clamping the blade within the slot.
 6. Structure as defined in claim 5 wherein said body has a thickness, on each side of each of said recesses, greater than the diameter of the recess. 